JP3236818B2 - Method for manufacturing multilayer wiring board with built-in element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer wiring board, and more particularly to a method for manufacturing a multilayer wiring board having a tape carrier package built in an insulating substrate.

[0002]

2. Description of the Related Art Conventionally, the miniaturization of electronic equipment has been progressing, and in recent years, with the development of portable information terminals and the spread of so-called mobile computing in which a computer is carried and operated, so-called multi-layer wiring of smaller, thinner and higher definition has been developed. Substrates tend to be required.

In addition, since the conventional multilayer wiring board has two-dimensionally mounted semiconductor elements on the front and back sides, there is naturally a limit to the high-density mounting of the wiring board. However, there is a problem that it becomes impossible to secure a space required for the electronic device, and it is impossible to cope with the thinning, miniaturization, and weight reduction of the printed circuit board accompanying the weight reduction and miniaturization of the electronic device.

On the other hand, as a method for mounting various electric elements at high density, CSP (chip size package), TSOP (Thin Small Outline Package), TC
For example, a package having a structure in which packages such as P are stacked in two or three layers, or a semiconductor element itself is stacked, for example, at the 23rd Seminar of the Circuit Packaging Society of Japan (October 1997
Monday) "Latest trends in semiconductor packages and packaging technology".

[0005]

However, in such a method of stacking packages and a method of stacking semiconductor elements, an area for routing a signal line for transmitting a signal to the semiconductor element is extremely limited. With the development of communication technology in the future, it has been very difficult to form complicated high-frequency transmission lines such as microstrip lines having a ground layer and a central conductor for transmitting high-frequency signals.

In addition, the method of simply stacking packages and semiconductor elements cannot be applied to mobile devices that need to be small and light because the overall thickness is inevitably large.

[0007] Based on such an idea, the present inventors,
First, a wiring circuit layer made of metal foil is formed on the transfer sheet,
A method has been devised in which a semiconductor element is connected to the wiring circuit layer and then transferred to an insulating layer to produce a multilayer wiring board incorporating one or more semiconductor elements. However, in this method, the operation of mounting a bare (naked) semiconductor element on a metal foil has to be performed in a high-performance clean room, so that it has been difficult to easily perform the operation.

Accordingly, the present invention provides a multilayer wiring board on which semiconductor elements and electronic components (capacitor elements, resistance elements, filter elements, oscillation elements, etc.) are mounted, and the semiconductor elements are three-dimensionally incorporated to reduce the size of the board. It is another object of the present invention to provide a method for manufacturing a multilayer wiring board that can easily manufacture a multilayer wiring board capable of increasing the element mounting density.

[0009]

As a result of repeated studies on miniaturization of a wiring board on which a semiconductor element is mounted, the present inventor has found that a resin having an electric element mounted on the surface of a tape carrier package or the like is provided in the wiring board. The film is laminated and integrated with the uncured insulating layer, and the laminate is heat-treated and cured. At this time, the resin film has heat resistance that does not deform at the heating temperature during thermosetting. By being formed by
And found that it can be built into the multilayer wiring board without adversely affecting the mounting structure of the electrical element.
The present invention has been reached.

That is, according to the method of manufacturing a multilayer wiring board with a built-in element of the present invention, a plurality of insulating layers including a thermosetting resin in an uncured state on which via-hole conductors and / or wiring circuit layers are formed are formed, and then these are formed. After having a glass transition point higher than the curing temperature of the thermosetting resin in the insulating layer between the insulating layers, and laminating and integrating a resin film having an electric element mounted on the surface thereof, The article is heated to the curing temperature of the thermosetting resin and is cured at once.

The electric element includes a semiconductor element, a capacitance element, a resistance element, and the like. Examples of the material of the heat-resistant resin film include imide resin, aramid resin, fluororesin, and PET (polyethylene terephthalate). Resin, PEN (polyethylene naphthalate)
Resins, polyolefin resins and the like are preferably used.

It is desirable that the electric element is accommodated in a void portion in the insulating layer, that the via-hole conductor is formed by filling metal powder, and that the wiring circuit layer is formed of metal foil.

[0013]

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining a manufacturing process for manufacturing a multilayer wiring board with a built-in element according to the present invention.

According to the manufacturing method of the present invention, as shown in FIG. 1, a plurality of insulating layers 3 containing an uncured thermosetting resin on which via-hole conductors 1 and / or wiring circuit layers 2 are formed are formed. After that, an electric element 4 is placed between these insulating layers 3.
Are laminated and integrated with each other.

A via-hole conductor 1 and a wiring circuit layer 2 are formed on the insulating layers 3a to 3d in FIG. 1. The via-hole conductor 1 is made of a soft (B-stage) insulating material containing a thermosetting resin. The via-hole conductor 1 can be formed by forming a through hole penetrating in the thickness direction in the layers 3a to 3d, and filling the through hole with a conductive paste containing a metal powder while performing screen printing or suction processing.

In order to form the wiring circuit layer 2 on the surfaces of the insulating layers 3a to 3d, 1) a method of forming a circuit pattern by attaching a metal foil to the surface of the insulating layer and etching the same; 3) A method in which a resist is formed on the surface of the insulating layer and formed by plating. 3) A metal foil is attached to the surface of the transfer film, and the metal foil is etched to form a circuit pattern. Is transferred to the surface of the insulating layer.

When the electric element formed on the resin film is bulky, the wiring board is deformed at the time of lamination. In such a case, as shown in FIG.
It is desirable to provide a gap 6 in the insulating layer 3b where the resin film 5 having the electric element 4 formed on the surface is laminated, so that the electric element 4 is stored in the gap 6 during lamination.

The resin film 5 on which the electric element 4 is formed is, for example, a tape carrier package (TCP) as shown in FIG. According to FIG.
The resin film 5 is formed in a frame shape. On the surface of the resin film 5, a wiring circuit layer 7 made of a metal foil led out from the inside of the frame to the outside is formed. The semiconductor element 8 is mounted on the surface of the wiring circuit layer 7. In addition, it is desirable that a substantially circular land having a diameter of 30 to 300 μm is formed at an end of the wiring circuit layer 7 outside the frame to facilitate connection with a via-hole conductor of an insulating layer sandwiching the resin film. . If there is no land, the connection with the via conductor, especially the alignment, may be difficult or the connection resistance may increase. It is desirable that the semiconductor element 8 mounted on the wiring circuit layer 7 be resin-sealed with the resin 9.

The sealing resin 9 plays a role of protecting the surface of the electric element during the manufacturing process, and also functions as insulating layers 3a to 3d.
It is used to reduce the difference between the thermal expansion coefficients of the semiconductor element 8 and the semiconductor element 8. Therefore, the resin contains 50% by volume or more of a filler such as SiO ₂ , and has a thermal expansion coefficient of 9 to 13 ppm / ° C. which is close to that of a semiconductor element. Those that relieve the stress due to the difference in thermal expansion are preferably used.

As another example of the resin film 5 on which the electric element 4 is formed, there is a resin film 5 on which a capacitance element as shown in FIG. 3 is formed. According to FIG. 3 (a), the resin film itself is formed of a high dielectric resin film 10 formed by mixing particles of high dielectric constant, and metal foil such as copper is coated on both surfaces as electrodes 11 and 11. 3B, a metal foil such as copper is formed as an electrode 13 on the surface of a resin film 12, and a dielectric material is formed on the surface thereof. One that forms a thin film 14, further forms an electrode 13 on the surface of the dielectric thin film 14, and can generate a capacitance between the electrodes 13 and 13.

According to FIG. 1, the resin film 5 on which these electric elements 4 are formed is connected to the wiring circuit layer 2 of the insulating layers 3a and 3b.
And the via-hole conductor 2 and an electrode or terminal of the electric element 4 are electrically connected to each other, and the laminate can be integrated by applying a pressure of 3 to 80 kg / cm ² .
Then, the above-described laminate is heated to a temperature at which the thermosetting resin in the insulating layers 3a to 3d can be completely cured, and these insulating layers are collectively thermally cured to form a multilayer containing the electric element 4. A wiring substrate can be manufactured.

According to the present invention, in the above-described manufacturing process, the resin film 5 on which the electric element 4 built in the multilayer wiring board is formed is made to have a temperature lower than the curing temperature of the thermosetting resin in the insulating layer 3 by glass. It is necessary to use a resin having a high transition point. If the glass transition point of the resin film 5 is lower than the curing temperature of the thermosetting resin, the resin film 5 on which the electric element 4 is formed is deformed at the time of complete curing in the manufacturing process, and the wiring with the electric element 4 is changed. May be disconnected or an electrical connection failure with the multilayer wiring board may occur. More specifically, it is desired that the glass transition point is higher than the thermosetting temperature by 10 ° C. or more, particularly 20 ° C. or more.

As such a heat-resistant resin film, the resin film may be selected from one of imide resin, aramid resin, fluorine resin, polyethylene terephthalate resin, polyethylene naphthalate resin and polyolefin resin. desirable.

In the above-mentioned manufacturing method, the insulating layer in the uncured state containing the thermosetting resin is formed by mixing the thermosetting organic resin or the composition of the thermosetting organic resin and the filler with a kneader or a three-roller. It is produced by forming a sheet by a rolling method, an extrusion method, an injection method, a doctor blade method or the like, and heat-treating the thermosetting resin as required to obtain a semi-cured resin. used. For semi-curing, the resin may be heated to a temperature slightly lower than a temperature sufficient to completely cure the resin.

The thermosetting resin forming the insulating layer is not particularly limited as long as it is a thermosetting resin having electrical properties, heat resistance and mechanical strength as an insulating material. , Aramid resin, phenolic resin,
Epoxy resins, imide resins, fluororesins, phenylene ether resins, bismaleide triazine resins, urea resins, melamine resins, silicone resins, urethane resins, unsaturated polyester resins, allyl resins and the like can be used alone or in combination.

In the insulating sheet 3, a filler can be compounded with an organic resin in order to increase the strength of the entire insulating substrate or wiring substrate. SiO ₂ , Al
Inorganic fillers such as ₂ O ₃ , TiO ₂ , AlN, SiC, and BaTiO ₃ are preferably used. Further, a nonwoven fabric or a woven fabric made of glass or aramid resin may be used by impregnating the above resin.

It is suitable that the organic resin and the filler are compounded in a volume ratio of 15:85 to 70:30.

The formation of through holes (via holes) and voids in the insulating layer is performed by drilling, punching,
A known method such as sandblasting or processing by irradiation with a carbon dioxide gas laser, a YAG laser, an excimer laser, or the like is employed. In particular, when forming the void, the insulating layer, from the viewpoint of workability by punching or laser among the various materials described above, epoxy resin, imide resin,
Most preferably, it is a mixture of a phenylene ether resin and a silica or aramid nonwoven fabric.

On the other hand, the metal paste filled in the via holes includes metal powder having an average particle size of 0.5 to 50 μm, such as copper powder, silver powder, silver-coated copper powder, and copper-silver alloy. If the average particle size of the metal powder is smaller than 0.5 μm, the contact resistance between the metal powders increases and the resistance of the through-hole conductor tends to increase. If the average particle size exceeds 50 μm, it is difficult to reduce the resistance of the through-hole conductor. Tend to be.

The conductive paste is prepared by adding and mixing the above-mentioned organic resin for binding and the solvent to the above-mentioned metal powder. The solvent to be added to the paste may be any solvent that can dissolve the binding organic resin to be used. For example, isopropyl alcohol, terpineol, 2-octanol, butyl carbitol acetate and the like are used. In addition, a paste made of a liquid resin such as an epoxy resin or a triallyl isocyanurate (TAIC) resin without using a solvent can also be used favorably.

As the organic resin for bonding in the above-mentioned conductor paste, cellulose and the like are used in addition to the above-mentioned organic resins constituting the various insulating sheets. This organic resin is
The metal powders are bonded in a state where they are in contact with each other, and the metal powders are bonded to the insulating sheet. This organic resin, in the metal paste,
It is desirable that the content is 0.1 to 40% by volume, particularly 0.3 to 30% by volume. This means that the amount of resin is 0.1.
If the amount is less than 1% by volume, it is difficult to bond the metal powders firmly to each other, and it is difficult to firmly adhere the low-resistance metal to the insulating layer. This makes it difficult to bring the powders into sufficient contact with each other and increases the resistance of the through-hole conductor.

As the wiring circuit layer, copper, aluminum,
It is desirable to be made of at least one kind or two or more kinds of alloys selected from the group of gold and silver, and particularly, copper or an alloy containing copper is most desirable. Further, for lowering the resistance of the wiring layer, a metal having a lower melting point than the low-resistance metal, for example,
A low melting point metal such as solder or tin may be contained in the metal component in the conductor composition at a ratio of 2 to 20% by weight.

In order to increase the adhesive strength between the wiring circuit layer and the insulating layer, the portion of the insulating layer where the wiring circuit layer is formed and / or the surface of the wiring circuit layer on the surface of the transfer film is 0.1 μm.
As described above, especially 0.3 μm to 3 μm, most preferably 0.3 μm to 1 μm.
It is desirable to roughen the surface to 5 μm. In order to seal both ends of the via-hole conductor with a wiring circuit layer made of a metal foil, the thickness of the wiring circuit layer 4 is appropriately 5 to 40 μm.

As described above, according to the present invention, a resin film in which an electric element such as a tape carrier package is formed in a multilayer wiring board having a plurality of insulating layers laminated by using a conventional laminating method. Can be mounted and stored,
Thereby, the density of the multilayer wiring board can be increased, and the size of the multilayer wiring board can be reduced.

[0036]

EXAMPLES Example 1 (1) Epoxy resin was added to a glass fiber woven fabric.
Equivalent to FR5 standard impregnated at volume%, thickness 100μ
prepreg A with a diameter of 0.1 mm using a carbon dioxide laser
A via hole is formed by filling a paste prepared by adding an appropriate amount of resin to a powder containing copper as a main component and tin and containing a small amount of silver, and a copper containing copper powder plated with silver in the via hole. A conductor was formed. Further, a void having a size of 12 mm × 12 mm for mounting a semiconductor element or an electronic component was formed in the prepreg using a mold.

(2) On the other hand, via holes are formed in a prepreg B made of the same material as the prepreg A with a laser,
The hole was filled with a copper paste containing copper powder plated with silver to form a via-hole conductor.

(3) On the other hand, an adhesive was applied to the surface of a transfer sheet made of polyethylene terephthalate (PET) resin, and a copper foil having a thickness of 12 μm and a surface roughness of 0.8 μm was adhered to one surface. Then, after applying a photoresist (dry film) and performing exposure and development, it was immersed in a ferric chloride solution to remove non-pattern portions by etching to form a wiring circuit layer. In addition, the produced wiring circuit layer is
This is a fine pattern having a line width of 20 μm and an interval between wirings of 20 μm.

(4) Then, the transfer sheet on which the wiring circuit layer formed in (3) is formed is positioned on the prepreg A prepared in (1), and the transfer sheet is pressure-bonded by applying a pressure of 50 kg / cm ^2. After that, the transfer film was peeled off, and the wiring circuit layer connected to the tape carrier package was transferred to the prepreg A.

(5) Thereafter, the semiconductor element was accommodated in the gap in (4), and the wiring circuit layer on the surface of the prepreg A and the land of the tape carrier package were positioned and installed.

The tape carrier package used was, as shown in FIG. 2, a wiring circuit comprising a polyimide resin, a resin film 5 having a glass transition point of 450 ° C. and a thickness of 32 μm, and a copper foil having a thickness of 18 μm. A layer 7 was formed, and a semiconductor element 8 mounted on the wiring circuit layer 7 was used. The periphery of the semiconductor element 8 was sealed by applying an epoxy resin 9.

(6) Next, the wiring circuit layer was transferred to the surface of the prepreg B prepared in (2) using a transfer sheet on which a wiring circuit layer made of a metal foil prepared in the same manner as in (3) was formed.

(7) Around the prepreg A in which the tape carrier package is housed and mounted in the gap, two prepregs, each having upper and lower wiring circuit layers formed thereon as shown in (6), are laminated on the upper and lower surfaces to 10 kg. / Cm ² and temporarily laminated.

(8) The laminate produced by (7) is
It was heated at 180 ° C. for 1 hour and cured at once to produce a multilayer wiring board with a built-in tape carrier package.

As a result of observing the vicinity of the formation of the wiring circuit layer and the via-hole conductor in the cross section of the obtained multilayer wiring board, a good connection was established between the tape carrier package IC element and the wiring circuit layer, and between the via-hole conductor and the wiring circuit layer. As a result of conducting a continuity test between the wirings, no disconnection of the wiring was observed. There was no problem in the operation of the IC element. The obtained multilayer wiring board was subjected to a humidity of 85.
%, For 100 hours in a high-temperature and high-humidity atmosphere at a temperature of 85 ° C.
As a comparison, as a tape carrier package,
A wiring circuit layer made of a copper foil having a thickness of 18 μm is formed on a resin film having a thickness of 32 μm made of an epoxy resin (glass transition point 150 ° C.), and a semiconductor element is mounted on the wiring circuit layer. Then, a device built-in multilayer wiring board was manufactured in exactly the same manner as above, and the same evaluation was performed. As a result, disconnection was observed between the semiconductor device and the wiring circuit phase.

Example 2 (1) A via hole having a diameter of 0.1 mm was formed by a carbon dioxide laser on a 150 μm thick semi-cured insulating layer A in which a glass cloth was impregnated with a PPE (polyphenylene ether) resin. A via-hole conductor was formed by filling a copper paste prepared by mixing a TAIC resin with a copper powder having silver plated therein and a tin-based powder as a main component. On the other hand, after bonding a copper foil to the surface of the transfer film, applying a photoresist (dry film) and performing exposure and development, this is immersed in a ferric chloride solution to remove non-pattern portions by etching. A wiring circuit layer is formed, the wiring circuit layer is aligned with the insulating sheet A and laminated, and 100 kg
Then, the transfer film was peeled off by pressure bonding at a pressure of / cm ² , and the wiring circuit layer was transferred to the insulating layer A.

(2) Next, a film prepared by plating copper on both surfaces of a polyimide film (glass transition point 500 ° C.) mixed with a high dielectric powder is cut into a predetermined shape, and the copper is etched to obtain a capacitance. Was adjusted to produce a film capacitor.

(3) The film-shaped capacitor produced in (2) was placed at a predetermined position on the insulating layer A.

(4) After that, the insulating layer B and the insulating layer C on which the via hole conductor and the wiring circuit layer are formed are sequentially superposed on the surface of the insulating sheet A on which the film-like capacitor is installed, in the same manner as in (1). Lamination and pressure bonding were performed at a pressure of 30 kg / cm ² .

(5) Then, the laminate of the insulating sheets A, B and C was heated at 195 ° C. while applying a pressure of 35 kg / cm ^2.
To complete hardening to produce a multilayer wiring board with a built-in capacitance element.

As a result of observing the vicinity of the formation of the wiring circuit layer and the via-hole conductor on the cross section of the obtained multilayer wiring board, the capacitor element and the wiring circuit layer and the via-hole conductor and the wiring circuit layer were in a good connection state. As a result of conducting a continuity test between the wirings, no disconnection of the wiring was observed. Also,
A predetermined capacitance could be obtained without any problem in the capacitance element. The obtained multilayer wiring board was left in a high-temperature and high-humidity atmosphere at a humidity of 85% and a temperature of 85 ° C for 100 hours.

For comparison, an epoxy resin film (glass transition point 150
(° C), using a copper-plated substrate on both sides and fabricating a multilayer wiring board with a built-in capacitive element in the same way as above, the film-like capacitor was deformed and the capacitance of the capacitive element changed significantly did.

[0053]

As described in detail above, according to the present invention,
In a multilayer wiring board on which semiconductor elements and electronic parts (capacitor elements, resistance elements, filter elements, oscillation elements, etc.) are mounted, a tape carrier package or a film-like electronic part in which electric elements are formed on a heat-resistant resin film is installed inside. By mounting the semiconductor device in a semiconductor device, it is possible to reduce the size of the substrate and increase the mounting density of the device by incorporating the semiconductor element three-dimensionally, and to easily form a high-density, high-definition, multifunctional wiring board. .

[Brief description of the drawings]

FIG. 1 is a process chart for explaining one embodiment of a method of manufacturing a multilayer wiring board with a built-in element according to the present invention.

FIG. 2 is a plan view illustrating a tape carrier package as an example of a resin film on which an electric element is formed.

FIG. 3 is a cross-sectional view for explaining an example of a resin film on which a capacitance element is formed as another example of a resin film on which an electric element is formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Via-hole conductor 2, 7 Wiring circuit layer 3, 3a-3d Insulating layer 4 Electric element 5, 10, 12 Resin film 6 Void 8 Semiconductor element 9 Sealing resin 11, 13 Electrode 14 Dielectric thin film

Claims (5)

(57) [Claims] 1. After a plurality of insulating layers including a thermosetting resin in an uncured state on which via-hole conductors and / or wiring circuit layers are formed, a thermosetting resin in the insulating layer is interposed between these insulating layers. Having a glass transition point higher than the curing temperature of the resin, after laminating and integrating a resin film having an electric element mounted on the surface thereof, heating the laminate to the curing temperature of the thermosetting resin. And a method of manufacturing a multilayer wiring board with a built-in element, which is simultaneously cured. 2. The method according to claim 1, wherein the via-hole conductor is formed by filling a paste containing a metal powder, and the wiring circuit layer is formed from a metal foil. 3. The method according to claim 1, wherein the electric element is a semiconductor element or a capacitive element. . 4. The element according to claim 1, wherein said resin film is made of one of an imide resin, an aramid resin, a fluororesin, a polyethylene terephthalate resin, a polyethylene naphthalate resin, and a polyolefin resin. Manufacturing method of built-in multilayer wiring board. 5. The method according to claim 1, wherein the electric element is housed in a void provided in the insulating layer.